AP_ADSB: support for provision of samples to other libraries

libraries/AP_ADSB/AP_ADSB.cpp

@@ -432,6 +432,9 @@ void AP_ADSB::update_vehicle(const mavlink_message_t* packet)
                     avoid_state.highest_threat_index = index;
                 }
     } // if buffer full
+
+    vehicle.last_update_ms = AP_HAL::millis() - vehicle.info.tslc;
+    push_sample(vehicle); // note that set_vehicle modifies vehicle
 }
 
 /*
@@ -677,3 +680,13 @@ void AP_ADSB::set_callsign(const char* str, const bool append_icao)
     out_state.cfg.callsign[sizeof(out_state.cfg.callsign)-1] = 0; // always null terminate just to be sure
 }
 
+
+void AP_ADSB::push_sample(adsb_vehicle_t &vehicle)
+{
+    samples.push_back(vehicle);
+}
+
+bool AP_ADSB::next_sample(adsb_vehicle_t &vehicle)
+{
+    return samples.pop_front(vehicle);
+}

libraries/AP_ADSB/AP_ADSB.h

@@ -25,6 +25,10 @@
 #include <AP_Common/AP_Common.h>
 #include <AP_Param/AP_Param.h>
 #include <AP_Common/Location.h>
+#include <GCS_MAVLink/GCS_MAVLink.h>
+#include <AP_AHRS/AP_AHRS.h>
+
+#include <AP_Buffer/AP_Buffer.h>
 
 class AP_ADSB
 {
@@ -84,6 +88,14 @@ public:
 
     UAVIONIX_ADSB_RF_HEALTH get_transceiver_status(void) { return out_state.status; }
 
+    // extract a location out of a vehicle item
+    Location_Class get_location(const adsb_vehicle_t &vehicle) const;
+
+    bool enabled() const {
+        return _enabled;
+    }
+    bool next_sample(adsb_vehicle_t &obstacle);
+
 private:
 
     // initialize _vehicle_list
@@ -95,9 +107,6 @@ private:
     // compares current vector against vehicle_list to detect threats
     void perform_threat_detection(void);
 
-    // extract a location out of a vehicle item
-    Location_Class get_location(const adsb_vehicle_t &vehicle) const;
-
     // return index of given vehicle if ICAO_ADDRESS matches. return -1 if no match
     bool find_index(const adsb_vehicle_t &vehicle, uint16_t *index) const;
 
@@ -184,4 +193,9 @@ private:
         float       highest_threat_distance;
     } avoid_state;
 
+    static const uint8_t max_samples = 30;
+    AP_Buffer<adsb_vehicle_t, max_samples> samples;
+
+    void push_sample(adsb_vehicle_t &vehicle);
+
 };